Base for incandescent lamps and similar devices



Dec. 26, 1939. c. A. BROWN El AL 2,184,269

BASE FOR INCANDESCENT LAMPS AND SIMILAR DEVICES Filed May 14, 1938Inventors:

Carl A- Brown, Clarence E. Hahn,

The'n Attorn' ey.

,. eiee e .Dee 19 9 i I fiaisiacc f,

else 'jij ocjiucm; ejceiiii .1 .s-i ,s ,oar'i a BrownfCha'rdon. andclarcnccnli. Hahn; Cleveland;Ohio,v assigirorsjtoaGeneral Electriccompany, acorporation of -New, York diipllcatlonlglayll'i. ia3a'.f senaine; 207,965

x0111 invention relates toielectric 1nca1{des' en." t hh,i8lhdthe brassj'shell orfiend zcontactyeyelet. .2 lamps; and similar devicescomprising'a bulbjhavf such a'rigid'inspection necessitates-a large in-1 an electrical energy; translation; element spectio'n'ior'ce; whichthereforefurthen increases sealed therein and a base mounted 'on'saldbulb. Qthe costjof'productionb i '5, More particularly, our, invention.relates to bases, Byri fif 'mih l' glass insulation a a .sepafor suchdevices which usually consist of a me ate rhemberand'thenmechanicallysecuring the 1;, tallic shelland -a bottomerid contactseparated bra's shell thereto, the above-mentioned-disadfrom each otherby a suitable insulating medium; vantages'are entirely obviated;"Accordingly, one In the presentmethod smanufacturingiama objectfot ourinvention is to'provide a base, con- .10' bases, a brass shell andacenter or end contact f struction' for electric lamps andsimilarrdevices ;-.;eyelet are first placedin a suitable moldand as inwhich the glass insulation consists of a sepa- 'definite quantity oimolt en glassipoured'therelFetelmfollllsd'Infinite!ill/111M115therssftelimeinto.A-plungerthenpresses the molten glass 'chanically securedto' the brassshelln s 1 into the desired shape and into firmen gagement Anotherobject of our invention is the-proviwith the brass shell and, yelet t thfbyf [sion'oi positive interlocking means between the 15 the completedbase. flhejhotglasalhowever, an-' ,f base shell andthe"preformed-:glass' insulation neals the brassshell so-that it isundesirably memberemp ye j Our i proved basev consoftened to the pointwhere it is readily deformstruction whereby relativerotational-displaceable, To partially compensate for theresulting mentbetween the'said parts is positively elimidecrease in strength or the,shell,,filldtoinainhated; m

tain the tshell vrtrengt h .aboy'e certai mi im m f A further object ofour inventlon is th iprovi- ,limits, it is therefore necessaryto'eniployibrass sion of a preformed; glass insulator button for a amaterial of greater thickness than would be the lamp b se th peripheryof which button is r case-lino suchannealirig actionwere' present. r d wt a plurel y f p i n 's shaped As a consequencelthe amount, andtherefore the as i and breakage during the rolling v 25 cost, of thebrass,ma terialj is considerably of the brass rhell onto saidprojections and to greater than'it would be, if 'no'such shell annealorma firm interlock between the brass shell ing occurred. F rthermore, thebrass shell is 4 and t e class buttons a I considerably tarnished ordiscolored by the heat Further objects and advantages of ourzinvenof themolten glassduring the formation of the 131011 w l pp from the followingdescription 30 base structure, thereby necesitating an opera-Y "of aspecies t e o and from the accompanying tion commonly known as abright-dip which drawin in Whitiht v consists in dipping the completedbases in a suitg- 1 is a fragmentary side View, P y in able acid bath,such as sulphuric and nitric acids, tion, of an electric incandescentlamp provided to remove the said discolorations and restore the w t a bse comprising 11 invention; 2 is 35 original brightness of the brassshell and eyelet. an enlarged fragmentary sectional view taken on Aconsiderable quantity of brass is removed from e ne of 3 is a p View Ofa the shell during this bright-dip operation, therepreformed glassinsulator button according to by resulting in a considerable waste ofmaterial our invention; an 4 is an a d se t ona 40 and so furtherincreasing the cost of manufacview taken on the line 4-4 of Fi 40 ture.Also, the acid etches the brass shell un- Referring to the drawing,there is shown in equally, etching the grain boundaries much Fig. 1 anelectric incandescent lamp Comprising 8 deeper than the grainsthemselves, so that the bulb l0 havin filament (not shown) sealedoriginal thickness of the brass must be suffitherein and a base Hattached to the neck ll of cient to compensate for such unequal etchingin the bulb by'sultable cement The base it 45 order to maintain thestrength of the shell above consists of a threaded metallic shell l Pcertain minimum limits. A further disadvanably of brass, to withinsulation '5, a tage of the above described process of manufacbottomend contact IS. The insulation is prefturing bases lies in the fact thatthe completed era ly mad f glass, although y other su tab e bases mustbe thoroughly inspected for a conma e y b employed- One 8nd of the p 50siderable number of objectionable defects, such filament is connected tothe base shell by means as missing eyelets, plugged eyelets, slanting orof a lead I! bent back over the end of the bulb displaced eyelets,threads of glass extending over neck and soldered at l8 to the edge ofthe said the edge of the shell, too much glass insulation, shell. Theother end of the lamp filament is a or an insecure bond between theglass insulaconnected to a lead H which extends through a 55 centrallylocated opening in the glass insulation where the said lead is Securedby means of a drop of solder I6 to thereby form the bottom end contact.The recess 2| in the glass insulation I5 is preferably shaped in themanner described and claimed in our co-pending application Serial No.207.964 of even date herewith.

The glass insulation I5 according to our invention is made as apreformed member and is secured to the base shell It by mechanicalinterlocking means. Referring to Fig. 1, the outer end of the base shellH is provided with a reentrant flange 22, the inner edge of which isbent inwardly to form an annular ledge or seat 23 on which the preformedglass button I5 is mounted. The upper or outer convex surface 24 (Fig.4)of the glass button l5, adjacent the periphery 25 thereof, is formedwith a plurality of uniformly spaced crescent shaped projections or lugs26. The upper surfaces 21 of these lugs are substantially flat and liein a plane approximately parallel to that of the seating surface 28 onthe glass button, while the side surfaces 29 of the lugs are formedsubstantially as continuations of the periphery 25, as shown in- Fig. 4,and are curved on a radius of preferably one-sixteenth inch orthereabouts.

In assembling the preformed glass button l5 and the base shell II, thebutton is simply placed in position on the annular seating flange 23 andthe upper edge 30 of the base shell isrolled or peened over the variousprojections 26 by means of a suitable forming tool,.such as a roller orcam. The pressure so applied to the edge 30 of the base shell results ina deformation of the reentrant flange 22 whereby the same conforms toand engages the curved side surfaces 29 of the various projections 26,as shown in Fig. 2, as well as'the upper surfagces 21 of the same. Toinsure such a deformaition of the re-entrant flange 22 without acorresponding deformat on of the outer edge or wall 30 of the baseshell, the projections 26 on the glass button are spaced a definitedistance apart. Thus, as shown in Fig. 3. a button l5 having a diameterof approximately seven-tenths of an inch is preferably provided withtwenty such projections 26 around its circumference so that the samewill be spaced approximately eleven-hundredths of an inch apart. Withsuch an arrangement, a positive interlock between the brass shell I4 andthe glass button I5 is assured whereby relative rotative displacementtherebetween is entirely prevented. In addition, the projections 26 aresufllciently strong so as not to become broken during the rolling overof the shell edge 30 onto the said projections.

As stated previously, the use of the preformed glass insulator button I5 greatly simplifies the production. of lamp bases and materiallydecreases the cost of manufacture thereof. The internal strains in sucha button can be removed by annealing the same prior to its assembly withthe brass shell so that the latter is not softened and tarnished by theheat attending such annealing operation. Since no discoloration of thebrass shell occurs, the customary bright-dip operation may be dispensedwith, thus permitting the use of thinner material for the brass shell.The use of a drop of solder as the bottom end contact eliminates thecustomary brass eyelet, thereby resulting in a further saving of brass.Finally, the use of a preformed insulator button eliminates aconsiderable number of the defects for which bases have been heretoforeinspected, with a resulting decrease in the cost of inspect-ion.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A base for electric lamps or similar devices comprising a metal shelland a preformed insulator button at'the upper end thereof, said buttonhaving a convex upper surface with a pinrality of small spacedcrescent-shaped projections at its periphery, said shell having at itsupper end a re-entrant flange portion terminating in an inwardlyextending flange forming a seat for the periphery of said button, theupper portion of said re-entrant flange being deformed to conform to theshape of the periphery of said button including the curved sides of saidprojections and overlying the upper surfaces thereof, theinterengagement of said flange portion with the sides of saidprojections preventing relative rotational movement between said shelland button, and the periphery of said button being firmly clampedbetween the said inwardly extending flange and the portion of saidre-entrant flange overlyingsaid projections.

2. A base as set forth in claim 1 wherein the insulator button consistsof a vitreous material.

CARL A. BROWN. CLARENCE E. HAHN.

